A computing device may protect information from tampering by storing the information in a portion of memory that is accessible in a system management mode (SMM) of the computing device. For example, a computing device may implement a firmware interface (FI) variable repository in such a portion of memory to protect the repository from tampering. In such examples, storing data in the FI variable repository may include triggering a system management interrupt (SMI) to cause the computing device to enter the SMM, in which the data may be written to the repository.